1. Technical Field
The present invention relates to an electronic apparatus mountable on a rack provided with structure of mounting the electronic apparatus. In particular, the present invention is suitable for a business-use audio power amplifier.
2. Background Art
Business-use audio power amplifier for PA (Public Address), SR (Sound Reinforcement), etc. is used at the permanent' facilities such as a hall, a theater, and a banquet hall, or a moving venue, such as a live concert, and an event. In order that such business-use audio power amplifier may comply with requirement specifications, such as high power, high efficiency, and robustness, most have a weight over 10 kg and are provided with a cooling fan.
Such business-use audio power amplifiers are used by mounting on a rack, since two or more sets are used simultaneously in many cases. When using business-use audio power amplifier at a moving venue, the number of business-use audio power amplifier(s) according to the moving venue are mounted on a rack at the venue.
Generally, in an electronic apparatus mountable on a rack, attaching parts are provided in right and left of the front panel, and in addition carry handles may be provided (Refer to Patent Document 1).
FIG. 6 is an explanatory diagram showing a first conventional example (Refer to Non-patent Document 1) of a business-use audio power amplifier. FIG. 6(a) is a top view, FIG. 6(b) is a right side view, and FIG. 6(c) is a front view.
In FIG. 6, the reference numeral 111 denotes a side board of a main chassis, and the reference numeral 112 denotes a top cover, the reference numeral 113 denotes a front panel, the reference numeral 114 denotes a carry handle, the reference numeral 115 denotes a rack angle, the reference numeral 116 denotes a through-hole (long hole), the reference numeral 117 denotes a screw, the reference numeral 118 denotes a fresh air inlet, the reference numeral 119 denotes a back plate, and the reference numerals 1201 to 1205 denote through-holes. The through-holes 1201, 1202, and 1204 are holes for the usual attachment which does not pass through a head of a screw although an axial part of a screw is passed through. However, the through-holes 1203 and 1205 are escape holes which let the head of a screw pass.
The rack angles 115 are metal fittings of L type, and are attached to the front panel 113 in a form where the right and left are extended, by securing the three screws 117 to screw holes formed on he side board of the main chassis through the through-holes 1201, 1202, and 1204.
On the other hand, the screw 117 passed through to the through-hole 1203 (escape hole) of the rack angle 115 passes through a through-hole formed in the side board on the right-hand side of the main chassis, and is secured to a screw hole formed in the sub chassis inside a case. As a result, the side board on the right-hand side of the main chassis and the sub chassis are fastened with each other.
Although the illustrated through-hole 1205 (escape hole) is not used, the through-hole 1205 is used with the through-holes 1201, 1202, and 1204 when attaching the same rack angle 115 to the other side board on the left-hand side of the main chassis. That is, the side board on the left-hand side of the main chassis and the sub chassis are fastened by passing a screw which passed through the through-hole 1205 (escape hole) through a through-hole formed in the side board on the left-hand side of the main chassis, and securing the screw to the screw hole of the sub chassis.
A power amplifier is mounted on a rack by abutting the front of a support part of the rack which is not illustrated to a rear face of the rack angle 115 attached to the side board 111 of the main chassis, passing a screw which is not illustrated through the through-hole 116, and securing the screw to a screw hole formed in the support part (vertical rail) or a screw hole of a cage nut provided in this support part. The carry handle 114 is attached inside rather than the side board 111 of right and left of the main chassis.
In the first conventional example mentioned above, since the carry handle 114 is attached within the case of power amplifier, this carry handle 114 covers the fresh air inlet 118, and reduces cooling efficiency of the cooling fan. Furthermore, even when the carry handle 114 is unnecessary, there is a problem that a user cannot remove the carry handle 114 easily.
FIG. 7 is an explanatory diagram showing a second conventional example (Refer to the Non-patent Document 2) of a business-use audio power amplifier. Only a front view in the state where a carry handle 122 is not attached is shown.
In FIG. 7, the reference numeral 121 denotes a front panel, the reference numeral 121a denotes an extended part of the front panel, the reference numeral 122 denotes a carry handle (shown by a dashed line), the reference numeral 123 denotes a through-hole (long hole), the reference numeral 124 denotes a through-hole, and the reference numeral 125 denotes a fresh air inlet.
The back side of the extended part 121a of the front panel lies outward from a side board of right and left of the main chassis which is not illustrated. The audio power amplifier is mounted on a rack by passing a screw to the through-hole (long hole) 123 provided in the extended part 121a of the front panel, and securing the screw to a support part of the rack. Therefore, a rack angle is integrally formed with the front panel 121.
Since the carry handle 122 is attached in the extended part 121a of the front panel, attachment/detachment is free for the carry handle 122. Moreover, since the carry handle 122 does not cover the fresh air inlet 125, it does not reduce cooling efficiency of a cooling fan.
However, as for the case of business-use audio power amplifier, the depth dimension tends to increase with requirement specifications, such as improvement in extendibility, and correspondence to a digital network.
However, in each conventional example, when a body of power amplifier with long depth dimension is mounted on the rack of standard specification, there is a problem that the case is not settled in the rack of standard specification. Even if the case is settled in the rack of standard specification, there is a problem that there is no space for wiring input and output terminals provided in a rear panel of the case.
[Patent Document 1] Japanese Patent Application Laid-open No. H09-199879
[Non-patent Document 1] “POWERAMPLIFIERXP7000/XP5000/XP3500/XP2500/XP1000 Operation Manual”, (online), YAMAHA CORP., (Searched June, 2007), the Internet (URL:http://www2.yamaha.co.jp/manual/pdf/pa/japan/amp/xp7000#ja.pdf), pages 6 and 15
[Non-patent Document 2] “POWER AMPLIFIER T5n/T4n/T3n Operation Manual”, (online), YAMAHA CORP., (Search for in June, 2007), the Internet (URL:http://www2.yamaha.co.jp/manual/pdf/pa/japan/amp/t5n#t4n#t3n#ja#om.pdf), pages 6/18 and 16/18